U.S. patent application number 16/364442 was filed with the patent office on 2019-10-17 for vehicle traveling controller.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Yutaro HAYASHI, Yoshinori WATANABE.
Application Number | 20190315404 16/364442 |
Document ID | / |
Family ID | 68161363 |
Filed Date | 2019-10-17 |
United States Patent
Application |
20190315404 |
Kind Code |
A1 |
HAYASHI; Yutaro ; et
al. |
October 17, 2019 |
VEHICLE TRAVELING CONTROLLER
Abstract
A vehicle traveling controller according to the present
disclosure performs automatic steering so that a vehicle travels
along a target path. The vehicle traveling controller allows a
driver to intervene in steering. When the driver intervenes in
steering and thereby a traveling position of the vehicle deviates
outside from a threshold line set apart from the target path in a
lane width direction, the vehicle traveling controller increases a
steering reaction force acting on steering operation by the
driver.
Inventors: |
HAYASHI; Yutaro; (Sunto-gun,
JP) ; WATANABE; Yoshinori; (Isehara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi |
|
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
68161363 |
Appl. No.: |
16/364442 |
Filed: |
March 26, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B62D 15/025 20130101;
B62D 6/008 20130101; B62D 15/0255 20130101; B62D 1/286
20130101 |
International
Class: |
B62D 15/02 20060101
B62D015/02; B62D 6/00 20060101 B62D006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 2018 |
JP |
2018-077803 |
Claims
1. A vehicle traveling controller that performs automatic steering
so that a vehicle travels along a target path, comprising: at least
one processor; and at least one memory coupled to the at least one
processor, the at least one memory including at least one
computer-executable program that upon execution causes the at least
one processor to: allow a driver to intervene in steering; and when
the driver intervenes in steering and thereby a traveling position
of the vehicle deviates outside from a threshold line set apart
from the target path in a lane width direction, increase a steering
reaction force acting on steering operation by the driver.
2. The vehicle traveling controller according to claim 1, wherein
the at least one computer-executable program upon execution causes
the at least one processor to increase the steering reaction force
in accordance with a deviation of the traveling position of the
vehicle from the threshold line.
3. The vehicle traveling controller according to claim 2, wherein
the at least one computer-executable program upon execution causes
the at least one processor to comprise: a traveling track
generation unit that generates a traveling track for converging the
traveling position of the vehicle to the target path; and a
tracking control unit that performs tracking control to make the
vehicle track the traveling track, wherein the traveling track
generation unit is configured to: generate the traveling track on
the basis of the traveling position of the vehicle when the driver
intervenes in steering but the traveling position of the vehicle
does not deviate outside from the threshold line; and generate the
traveling track on the basis of a threshold position set on the
threshold line when the driver intervenes in steering and thereby
the traveling position of the vehicle deviates outside from the
threshold line.
4. The vehicle traveling controller according to claim 3, wherein
the traveling track generation unit is configured, in a case where
a direction indicator is operated to a steering direction of the
driver, to generate the traveling track on the basis of the
traveling position of the vehicle irrespective of a positional
relation between the traveling position of the vehicle and the
threshold line.
5. The vehicle traveling controller according to claim 3, wherein
the traveling track generation unit is configured, in a case where
a road shape in front of the vehicle is a road shape requiring a
lane change from a traveling lane, to generate the traveling track
on the basis of the traveling position of the vehicle irrespective
of a positional relation between the traveling position of the
vehicle and the threshold line.
6. The vehicle traveling controller according to claim 3, wherein a
setting of a position of the threshold line is changed in
accordance with a traveling environment of the vehicle.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Japanese Patent
Application No. 2018-077803, filed on Apr. 13, 2018, which is
incorporated by reference herein in its entirety.
BACKGROUND
Field
[0002] The present disclosure relates to a vehicle travelling
controller, especially a vehicle traveling controller that performs
automatic steering so that a vehicle travels along a target
path.
Background Art
[0003] As disclosed in US2009/0319113A for example, various methods
to make a vehicle travel along a target path (for example, a center
line of a lane) are proposed. As one of such methods, it is known,
in a case where a traveling position of the vehicle deviates from
the target path, to generate a traveling track toward the target
path from the current position of the vehicle and return the
vehicle to the target path by making the vehicle track the
traveling track.
SUMMARY
[0004] One of the reason why the traveling position of the vehicle
deviates from the target path is an intervention by the driver in
steering. A deviation of the traveling position of the vehicle may
cause danger. Therefore, if the deviation of the traveling position
of the vehicle is due to the intervention by the driver in
steering, it is required to call the driver's attention. However,
depending on how to call the driver's attention, the driver feels
annoyed.
[0005] The present disclosure has been devised in view of such
problems, and an object of the present disclosure is to provide a
vehicle travelling controller capable of calling the driver's
attention without making the driver feel annoyed when the vehicle
under automatic steering may deviate from the target path by the
intervention by the driver in steering.
[0006] A vehicle travelling controller according to the present
disclosure is a vehicle travelling controller that performs
automatic steering so that a vehicle travels along a target path.
The vehicle travelling controller is configured to allow a driver
to intervene in steering, and is configured, when the driver
intervenes in steering and thereby a traveling position of the
vehicle deviates outside from a threshold line, to increase a
steering reaction force acting on steering operation by the driver.
The threshold line is set apart from the target path in a lane
width direction.
[0007] According to the vehicle travelling controller configured as
above, as the steering reaction force increases when the traveling
position of the vehicle deviates outside from the threshold line,
it is possible to inform the driver of a deviation of the vehicle
from the target path efficiently by the steering reaction force
increasing. Also, if the deviation does not exceed the threshold
line, there is little risk that the driver feels annoyed with
respect to the steering reaction force.
[0008] The vehicle travelling controller may be configured to
increase the steering reaction force in accordance with the
deviation of the traveling position of the vehicle from the
threshold line. This makes it possible to call the driver's
attention strongly as the deviation from the target path becomes
large.
[0009] The vehicle travelling controller may comprise, as means for
realizing the above functions, a traveling track generation unit
that generates a traveling track for converging the traveling
position of the vehicle to the target path, and a tracking control
unit that performs tracking control to make the vehicle track the
traveling track. The traveling track generation unit generates the
traveling track on the basis of the traveling position of the
vehicle when the driver intervenes in steering but the traveling
position of the vehicle does not deviate outside from the threshold
line. Further, the traveling track generation unit generates the
traveling track on the basis of a threshold position set on the
threshold line when the driver intervenes in steering and thereby
the traveling position of the vehicle deviates outside from the
threshold line.
[0010] When the traveling position of the vehicle is used as the
basis of the traveling track, the vehicle doesn't deviate from the
traveling track, and thereby the steering reaction force acting on
steering operation by the driver by the tracking control is
suppressed. On the other hand, when the threshold line is used as
the basis of the traveling track, the steering reaction force
acting on steering operation by the driver by the tracking control
increases as the traveling position of the vehicle deviates outside
from the threshold line greatly. Therefore, according to the above
configuration, until the traveling position of the vehicle deviates
outside from the threshold line, it is possible to allow steering
operation by the driver, and when the traveling position of the
vehicle deviates outside from the threshold line, it is possible to
call the driver's attention by the steering reaction force
increasing in accordance with the deviation amount.
[0011] The traveling track generation unit may be configured, in a
case where a direction indicator is operated to a steering
direction of the driver, to generate the traveling track on the
basis of the traveling position of the vehicle irrespective of a
positional relation between the traveling position of the vehicle
and the threshold line. When the direction indicator is operated,
it can be assumed that the driver is making the traveling position
of the vehicle deviate from the target path intentionally. In this
case, by generating the traveling track on the basis of the
traveling position of the vehicle so as to suppress the steering
reaction force acting on steering operation by the driver, the
driver can steer the vehicle to the intended direction without
being disturbed by the steering reaction force.
[0012] The traveling track generation unit may be configured, in a
case where a road shape in front of the vehicle is a road shape
requiring a lane change from a traveling lane, to generate the
traveling track on the basis of the traveling position of the
vehicle irrespective of a positional relation between the traveling
position of the vehicle and the threshold line. When the traveling
position of the vehicle deviates from the target path under the
road shape requiring a lane change from the traveling lane, it can
be assumed that the deviation is caused by the driver's intention.
In this case, by generating the traveling track on the basis of the
traveling position of the vehicle so as to suppress the steering
reaction force acting on steering operation by the driver, the
driver can steer the vehicle to the intended direction without
being disturbed by the steering reaction force.
[0013] A setting of a position of the threshold line may be changed
in accordance with a traveling environment of the vehicle. This
makes it possible to change the attention level of calling the
driver's attention in accordance with the traveling environment of
the vehicle.
[0014] As described above, according to the vehicle travelling
controller according to the present disclosure, it is possible to
call the driver's attention without making the driver feel annoyed
when the vehicle under automatic steering may deviate from the
target path by the intervention by the driver in steering.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a block diagram illustrating a configuration of a
control system of an automated driving vehicle equipped with a
vehicle travelling controller according to the present
disclosure;
[0016] FIGS. 2 and 3 are diagrams illustrating how to generate a
traveling track and the effect thereof;
[0017] FIG. 4 is a flowchart showing a specific routine to generate
the traveling track;
[0018] FIGS. 5 and 6 are diagrams illustrating examples of setting
of the threshold line; and
[0019] FIGS. 7 and 8 are diagrams illustrating exceptions in a
deviation determination for setting a traveling track base
point.
DETAILED DESCRIPTION
[0020] Hereunder, an embodiment of the present disclosure will be
described with reference to the drawings. Note that when the
numerals of numbers, quantities, amounts, ranges and the like of
respective elements are mentioned in the embodiment shown as
follows, the present disclosure is not limited to the mentioned
numerals unless specially explicitly described otherwise, or unless
the disclosure is explicitly specified by the numerals
theoretically. Furthermore, structures and steps that are described
in the embodiment shown as follows are not always indispensable to
the disclosure unless specially explicitly shown otherwise, or
unless the disclosure is explicitly specified by the structures or
the steps theoretically.
1. Configuration of Control System of Automated Driving Vehicle
[0021] The vehicle traveling controller according to the present
embodiment is a vehicle traveling controller for automated driving,
and is installed in an automated driving vehicle. Also, the vehicle
traveling controller is a controller capable of realizing, for
example, an automated driving level equal to or more than Level 2
defined by SAE (Society of Automotive Engineers). The automated
driving vehicle equipped with the vehicle traveling controller has
a control system of which the configuration is illustrated by, for
example, a block diagram of FIG. 1.
[0022] In the control system of the automated driving vehicle
(hereafter, simply referred to as vehicle) 1, various kinds of
sensors 4, 5, 6 and various kinds of actuators 7, 8, 9 are
connected to the vehicle traveling controller 10. The vehicle
traveling controller 10 is configured to fetch signals from the
various kinds of sensors 4, 5, 6, obtain operation signals by
processing the fetched signals, and operate the various kinds of
actuators 7, 8, 9 by the operation signals.
[0023] The various kinds of sensors 4, 5, 6 include an external
sensor 4 that acquires information on the surrounding environments
and peripheral objects of the vehicle 1, a vehicle sensor 5 that
acquires information on the motion states of the vehicle 1, a
steering sensor 6 that detects a steering operation by the driver.
Specifically, the external sensor 4 includes at least a camera that
takes an image of an environment in front of the vehicle 1. A
millimeter wave radar and a LIDAR (Laser Imaging Detection and
Ranging) may be provided as the external sensor 4. The vehicle
sensor 5 includes, for example, a vehicle speed sensor that
measures the travelling speed of the vehicle 1 from the rotation
speed of a wheel, an acceleration sensor that measures the
acceleration acting on the vehicle 1, and a yaw rate sensor that
measures the turning angular velocity of the vehicle 1. The
steering sensor 6 includes, for example, a steering angle sensor
that measures the steering angle of a steering shaft and a steering
torque sensor that measures the torque acting on the steering
shaft. These sensors 4, 5, 6 are connected to the vehicle traveling
controller 10 directly or via a communication network such as CAN
(Controller Area Network) built in the vehicle 1.
[0024] The various kinds of actuators 7, 8, 9 includes a steering
actuator 7 for steering the vehicle 1, a braking actuator 8 for
decelerating the vehicle 1, and a driving actuator 9 for
accelerating the vehicle 1. The steering actuator 7 includes, for
example, a power steering system using a motor or hydraulic
pressure, and a steer-by-wire steering system. The braking actuator
8 includes, for example, a hydraulic brake and a power regenerative
brake. The driving actuator 9 includes, for example, an engine, an
EV system, a hybrid system, a fuel cell system and the like.
[0025] The vehicle traveling controller 10 is an ECU (Electronic
Control Unit) comprising at least one CPU, at least one ROM, and at
least one RAM. In the at least one ROM, various kinds of programs
for automatic steering and various kinds of date including a map
are stored. When at least one program stored in the at least one
RAM is loaded on the at least one RAM, and is executed by the at
least one CPU, various kinds of functions are realized by the
vehicle traveling controller 10. Note that the vehicle traveling
controller 10 may be constituted of a plurality of ECUs.
2. Functions of Vehicle Traveling Controller
[0026] In FIG. 1, among the functions of the vehicle traveling
controller 1, in particular, functions relating to automatic
steering are represented by blocks. Other functions of the vehicle
traveling controller 1 are omitted in FIG. 1. Hereafter, functions
of the vehicle traveling controller 1 will be described.
[0027] The vehicle traveling controller 10 has functions for
automatically steering so that the vehicle travels along a target
path. These functions are realized by a traveling lane recognition
unit 11, a peripheral environment recognition unit 12, a steering
intervention detection unit 13, a traveling track generation unit
14, a tracking control unit 15 and an actuator operation unit 16
which constitute the vehicle traveling controller 10. However,
these units don't exist as hardware in the vehicle traveling
controller 10, but are realized by software when the at least one
program stored in the at least one ROM is executed by the at least
one CPU.
[0028] The traveling lane recognition unit 11 processes images
taken by a camera included in the external sensor 4 and recognizes
a lane marker such as an outside line, a boundary line and a center
line. Then, the traveling lane recognition unit 11 recognizes the
traveling lane on which the vehicle 1 is travelling, based on the
position of the lane marker on a vehicle coordinate system. The
vehicle coordinate system is a coordinate system of which the
center is set at a reference point set on the vehicle 1. The
traveling lane recognition unit 11 sets a target path of the
vehicle 1 based on the recognized lane marker. For example, the
center line of the traveling lane may be set as the target path of
the vehicle 1. In addition, if the vehicle 1 comprises a GPS
receiver and a database storing map information, the traveling lane
recognition unit 11 may recognize the traveling lane by using GPS
positional information and map information and set the target path
based on the recognized results.
[0029] The peripheral environment recognition unit 12 recognizes an
object that exists in the periphery of the vehicle 1. Recognition
of a peripheral object is performed by using information acquired
from the external sensor 4. The peripheral environment recognition
unit 12 performs the recognition of the peripheral object by using
at least one of information acquired by the camera, information
acquired by the millimeter wave radar, information acquired by the
LIDAR and information acquired by multiple sensors in combination
by sensor fusion. The peripheral object that is recognized includes
a moving object such as a pedestrian, a bicycle and a vehicle, and
a stationary object (obstacle) such as a stopped vehicle, a
guardrail, a building and a tree.
[0030] The steering intervention detection unit 13 detects an
intervention by the driver in steering under automated driving. The
intervention by the driver in steering is detected by using
information acquired by the steering sensor 6. The steering
intervention detection unit 13 determines that the driver is
intervening in steering, for example, when a steering torque
exceeding a predetermined value is continuously measured for a
predetermined time by the steering torque sensor. Also, it may be
determined that the driver is intervening in steering when a
steering operation more than a predetermined angle is measured by
the steering angle sensor.
[0031] The traveling track generation unit 14 generates a traveling
track for converging the traveling position of the vehicle 1 to the
target path. Specifically, the traveling track generation unit 14
calculates a traveling track function of which the variable is an
elapsed time from the current position. The variable is represented
by, for example, the following quintic function. Here, "t"
represents time. "y(t)" represents the target lateral position of
the vehicle 1 with respect to the target path at time t. "c0",
"c1", "c2", "c3", "c4" and "c5" represent coefficients. Note that
"lateral position" means the relative position of the vehicle 1
with respect to the target path in the lane width direction.
y(t)=c0+c1*t+c2*t.sup.2+c3*t.sup.3+c4*t.sup.4+c5*t.sup.5
[0032] The traveling track function y(t) is made to move the
vehicle 1 from a base point to an end point smoothly. The base
point of the traveling track is the current traveling position of
the vehicle 1 basically. However, as will be described in detail
later, when a predetermined condition is satisfied, the base point
of the traveling track is set to a position different from the
current traveling position. The end point of the traveling track is
set on the target path ahead of the vehicle 1. The distance from
the base point to the end point along the target path may be a
fixed value, or may be changed, for example, in accordance with the
speed of the vehicle 1.
[0033] The coefficients c0, c1, c2, c3, c4, c5 of the traveling
track function y(t) are determined based on the current conditions
of the vehicle 1 and the target conditions of the vehicle 1 at the
end point. Specifically, the coefficients c0, c1, c2, c3, c4, c5
for moving the vehicle 1 smoothly from the current position and
converging the traveling position of the vehicle 1 to the target
path smoothly are calculated by using, for example, the lateral
position of the base point with respect to the target path, the
current lateral speed of the vehicle 1, the current lateral
acceleration of the vehicle 1, the target lateral speed of the
vehicle 1 at the end point and the target lateral acceleration of
the vehicle 1 as parameters.
[0034] In addition, when generating the traveling track, the
traveling track generation unit 14 sets a threshold line apart from
the target path in a lane width direction. The threshold line is a
traveling position at which attention to the driver is begun to be
called when the traveling position of the vehicle 1 deviates from
the target path due to the steering intervention by the driver. The
traveling track generation unit 14 sets the threshold line based on
the recognition result by the peripheral environment recognition
unit 12. The method of setting the threshold line will be described
in detail later.
[0035] The tracking control unit 15 performs tracking control for
making the vehicle track the traveling track. The tracking control
includes feed-forward control. Concretely, in the feed-forward
control, a control point on the traveling track (which is a center
point if the traveling track is a lane center line) at the time
after a predetermined time from the current time is set as a
reference point. Then, a feed-forward value of the operation amount
of the steering actuator 7 is calculated from a parameter
corresponding to the reference point. The parameter that is
referred when calculating the feed-forward value includes, for
example, a curvature of the traveling track.
[0036] The tracking control performed by the tracking control unit
15 includes feed-back control. The feed-back control is, for
example, PI control, PD control, or PID control. In the feed-back
control, a path of the vehicle 1 is predicted by using such
information as vehicle speed, yaw rate and steering angle measured
by the vehicle sensor 5. Then, a predicted position and predicted
yaw angle of the vehicle 1 at the time after a predetermined time
from the current time is calculated based on the predicted
path.
[0037] In the feed-back control, next, a feed-back correction
amount of the operation amount is calculated based on a parameter
indicating the magnitude or tendency of the deviation between the
reference point on the traveling point and the predicted position
of the vehicle 1. The parameter that is referred when calculating
the feed-back correction amount includes, for example, a lateral
deviation and a yaw angle deviation. The lateral deviation is a
deviation in the lane width direction between the reference point
and the predicted position of the vehicle 1. The yaw angle
deviation is a deviation between the tangent angle of the traveling
track at the reference point and the predicted yaw angle of the
vehicle 1 at the predicted position. The tracking control unit 15
calculates the sum of the feed-forward value and the feed-back
correction amount as the operation amount of the steering actuator
7.
[0038] The actuator operation unit 16 operates the steering
actuator 7 by using the operation amount calculated by the tracking
control unit 15. As described above, the operation amount includes
the feed-forward value and the feed-back correction amount. If the
feed-back correction amount is generated by the deviation of the
traveling position of the vehicle 1 from the traveling track due to
the steering intervention by the driver, the steering force of the
steering actuator 7 generated by the feed-back correction amount
acts on steering operation by the driver as a steering reaction
force.
3. How to Generate Traveling Track and Effect Thereof
[0039] How to generate a traveling track by the traveling track
generation unit 14 and the effect thereof will be described by
using FIGS. 2 and 3. FIGS. 2 and 3 show the positional relation
between the vehicle 1 on the reference coordinate system, the lane
markers 31, 32 defining the traveling lane 30, the target path 34
and the threshold line 36. The reference coordinate system is a
coordinate system with the widthwise direction of the traveling
lane as the horizontal axis and the extending direction of the
traveling lane as the vertical axis. The reference coordinate
system is updated in accordance with the movement of the vehicle 1
so that a base point 22 set on the vehicle 1 is always on the
horizontal axis of the reference coordinate system. Note that the
base point 22 is a point indicating the traveling position of the
vehicle 1. In the present embodiment, the based point 22 is set on
the center of the rear end of the vehicle 1. Hereafter, the base
point 22 will be referred as the traveling position 22 of the
vehicle 1.
[0040] In FIGS. 2 and 3, the traveling position 22 of the vehicle 1
deviates from the target path 34 due to the steering intervention
by the driver. However, although FIG. 2 shows an example that the
traveling position 22 of the vehicle 1 doesn't deviate outside from
the threshold line 36, FIG. 3 shows an example that the traveling
position 22 of the vehicle 1 deviates outside from the threshold
line 36. The traveling track generation unit 14 changes how to
generate the traveling track in accordance with the positional
relation between the traveling position 22 of the vehicle 1 and the
threshold line 36.
[0041] When the traveling position 22 of the vehicle 1 doesn't
deviate outside from the threshold line 36, the traveling track
generation unit 14 generates the traveling track 20 with the
traveling position 22 of the vehicle 1 as the base point as shown
in FIG. 2. That is, when calculating the traveling track function,
the lateral position of the traveling position 22 of the vehicle 1
with respect to the target path 34 is used in the calculation of
the coefficients c0, c1, c2, c3, c4, c5. Thereby, the traveling
track 20 is generated to connect to the end point 24 on the target
path 34 smoothly with the current traveling position 22 of the
vehicle 1 as the base point.
[0042] The traveling track generation unit 14 calculates the
traveling track function in an operation period of the vehicle
traveling controller 10 and updates the position of the traveling
track 20. When the predicted position after a predetermined time
period that depends on the predicted path of the vehicle 1 deviates
from the reference point on the traveling track 20, or when the
predicted yaw angle of the vehicle 1 after a predetermined time
period deviates from the tangent angle of the traveling track at
the reference point, the feed-back correction amount is calculated
in the calculation of the operation amount by the tracking control
unit 15. However, when the traveling position 22 of the vehicle 1
doesn't deviate outside from the threshold line 36, the current
traveling position 22 of the vehicle 1 is used as the base point of
the traveling track 20, and thereby a deviation isn't generated
between the current traveling position 22 of the vehicle 1 and the
traveling track 20. Therefore, the feed-back correction amount
calculated in this case is not large, and the steering reaction
force acting on steering operation by the driver is suppressed.
[0043] When the traveling position 22 of the vehicle 1 deviates
outside from the threshold line 36, the traveling track generation
unit 14 generates the traveling track 20 with a threshold position
26 set on the threshold line 36 as the base point as shown in FIG.
3. The threshold position 26 is a point at which the threshold line
36 intersects the horizontal axis (not shown) of the reference
coordinate system. When calculating the traveling track function,
the lateral position of the threshold position 26 with respect to
the target path 34 is used in the calculation of the coefficients
c0, c1, c2, c3, c4, c5. Thereby, the traveling track 20 is
generated to connect to the end point 24 on the target path 34
smoothly with the threshold position 26 as the base point.
[0044] By the traveling track 20 being generated with the threshold
position 26 as the base point, the traveling position 22 of the
vehicle 1 deviates from the traveling track 20. This deviation
increases the feed-back correction amount calculated by the
tracking control unit 15 and increases the steering reaction force
acting on steering operation by the driver. The steering reaction
force acting on steering operation by the driver becomes larger as
the deviation d of the traveling position 22 of the vehicle 1 from
the threshold line 36 increases. For example, at the traveling
position 22' of the vehicle 1' shown by a dotted line in the
figure, the deviation amount d' becomes larger than the deviation
amount d at the position shown by a solid line, and thereby the
steering reaction force acting on steering operation by driver
becomes larger.
[0045] As described above, by changing how to generate the
traveling track 20 in accordance with the positional relation
between the traveling position 22 of the vehicle 1 and the
threshold line 36, it becomes possible to call the driver's
attention without making the driver feel annoyed when the vehicle 1
may deviate from the target path 34 by the intervention by the
driver in steering. Concretely, until the traveling position 22 of
the vehicle 1 deviates outside from the threshold line 36, the
steering reaction force is suppressed to allow steering operation
by the driver. Also, when the traveling position 22 of the vehicle
1 deviates outside from the threshold line 36, it is possible to
notify the driver of the deviation of the vehicle 1 from the target
path 34 effectively by the steering reaction force increasing in
accordance with the deviation amount.
4. Specific Routine to Generate Traveling Track
[0046] FIG. 4 is a flowchart showing a specific routine for the
traveling track generation unit 14 to generate the traveling track
20. The traveling track generation unit 14 executes the routine
shown in this flowchart in the operation period of the vehicle
traveling controller 10.
[0047] First, in step S11, it is determined whether or not the
intervention by the driver in steering is detected by the steering
intervention detection unit 13. When the intervention by the driver
in steering is detected, the routine proceeds to step S12.
[0048] In step S12, setting of the threshold line 36 is executed.
How to set the threshold line 36 will be described later. In step
S13, it is determined whether or not the traveling position 22 of
the vehicle 1 deviates outside from the threshold line 36. When the
traveling position 22 of the vehicle 1 deviates outside from the
threshold line 36, the routine proceeds to step S14. In step S14,
the threshold position 26 on the threshold line 36 is set as the
base point of the traveling track 20 (refer to FIG. 3).
[0049] When it is determined that the traveling position 22 of the
vehicle 1 doesn't deviate outside from the threshold line 36 in
step S13, the routine proceed to step S15. In step S15, the current
traveling position 22 of the vehicle 1 is set as the base point of
the traveling track 20 (refer to FIG. 2).
[0050] After processing in step S14 or step S15, the routine
proceeds to step S17. In step S17, the end point 24 of the
traveling track 20 is set on the target path 34. After processing
in step S17, the routine proceeds to step S18. In step S18, the
traveling track 20 is generated so as to connect the base point set
in step S14 or step S15 with the end point set in step S17
smoothly.
[0051] When the intervention by the driver in steering isn't
detected in step S11, the routine proceeds to step S16. When the
driver doesn't intervene in steering, the vehicle 1 travels along
the target path 34 and the traveling position 22 of the vehicle 1
is on the target path 34. Thus, a center point sequence of the
target path 34 is acquired in step S16. After processing in step
S16, the routine proceeds to step S18. In step S18, the traveling
track 20 is generated by connecting the center point sequence of
the target path 34 acquired in step S16.
5. Setting of Threshold Line
[0052] The threshold line 36 can be set arbitrary in accordance
with a traveling environment of the vehicle 1. For example, in a
traveling environment where suppressing the deviation of the
vehicle 1 from the target path 34 is required, the threshold line
36 may be set with a fixed distance from the target path 34 to the
outer direction in the lane width direction. As the time required
for the vehicle 1 to travel from the target path 34 to the
threshold line 36 depends on the speed of the vehicle 1, the
distance from the target path 34 to the threshold line 36 may be
changed in accordance with the speed of the vehicle 1.
[0053] In a traveling environment where preventing the vehicle 1
from approaching to the lane marker 31 is required, the threshold
line 36 may be set with a fixed distance from the lane marker 31 to
the inner direction in the lane width direction. The distance
between the lane marker 31 and the threshold line 36 may be changed
in accordance with a kind of the lane marker 31. For example, if
the lane marker 31 is a lane boundary, the distance between the
threshold line 36 and a yellow lane boundary may be longer than the
distance between the threshold line 36 and a white lane boundary.
The distance between the lane marker 31 and the threshold line 36
may be changed in accordance with the speed of the vehicle 1.
[0054] Also, when the lane marker 31 is a lane outside line, a road
structure 40 may be provided outside the lane marker 31 as shown in
FIG. 5. The road structure 40 includes, for example, a guard rail,
a wall, a curb stone and the like. In this case, the threshold line
36 may be set based on the position of the road structure 40. For
example, a line separated by a fixed distance from the road
structure 40 may be set as the threshold line 36. The distance
between the threshold line 36 and the road structure 40 may be
changed in accordance with the speed of the vehicle 1. When the
peripheral environment recognition unit 12 recognizes people,
animals and so on, the threshold line 36 may be set based on them
in order to prevent the vehicle 1 from contacting with them.
[0055] Further, the position of the threshold line 36 may be
changed in according with the presence or absence of another
vehicle 2 in the periphery of the vehicle 1. In the example shown
in FIG. 6, another vehicle 2 is traveling on the adjacent lane 38
adjacent to the traveling lane 30 across the lane boundary 33. The
vehicle 1 deviating outside from the lane boundary 33 in such a
case is dangerous compared with the case where another vehicle 2 is
not traveling in the adjacent lane 38. Then, a detection range 50
may be set in the adjacent lane 38 and the position of the
threshold line 36 may be changed depending on whether or not
another vehicle 2 is in the detection range 50. For example, the
threshold line 36' set in a case where another vehicle 2 is in the
detection range 50 may be set apart from the lane boundary 33 more
than the threshold line 36 set in a case where another vehicle 2
isn't in the detection range 50.
[0056] The vehicle traveling controller 10 may has a function of
issuing an alert when the traveling position 22 of the vehicle 1
deviates outside from the lane marker 31, 33. In this case, the
threshold line 36 may be set at a position where the steering
reaction force acts on the driver before the alert being
issued.
6. Exceptions in Deviation Determination for Setting Traveling
Track Base Point
[0057] In the above described embodiment, setting of the base point
of the traveling track 20 is changed depending on whether or not
the traveling position 22 of the vehicle 1 deviates outside from
the threshold line 36. However, when the deviation of the traveling
position 22 of the vehicle 1 from the target path 34 is caused by
the driver's intention, the steering reaction force generated by
changing the setting of the base point of the traveling track 20
interrupts the driver's intentional steering. Then, in a condition
where the deviation of the traveling position 22 of the vehicle 1
from the target path 34 can be performed by the driver
intentionally, the traveling track 20 may be generated with the
traveling position 22 of the vehicle 1 as the base point
irrespective of the positional relation between the traveling
position 22 of the vehicle 1 and the threshold line 36.
[0058] As an example of the intentional deviation of the traveling
position 22 of the vehicle 1 from the target path 34, a lane change
can be cited. As shown in FIG. 7, when the vehicle 1 is steered
from the traveling lane 30 toward the adjacent lane 38 and the
direction indicator 3 indicating the steering direction is
lighting, there is a high possibility that the driver performs the
intentional deviation of the traveling position 22 of the vehicle 1
from the target path 34 to try the lane change. Therefore, when the
direction indicator 3 is operated so as to indicate the steering
direction of the driver, the traveling track may be generated with
the traveling position 22 of the vehicle 1 as the base point so as
to suppress the steering reaction force acting on steering
operation by the driver. This allows the driver to steer the
vehicle to the intended direction without being disturbed by the
steering reaction force.
[0059] Further, as shown in FIG. 8, when a road shape in front of
the vehicle 1 is a junction or a lane decreasing point, it is
necessary to perform the lane change from the traveling lane 30 to
the adjacent lane 38. When the traveling position 22 of the vehicle
1 deviates from the target path 34 under such the road shape, it
can be presumed that the deviation is performed by the driver
intentionally even if the direction indicator 3 is not operated,
and therefore, the traveling track may be generated with the
traveling position of vehicle 1 as the base point so as to suppress
the steering reaction force acting on steering operation by the
driver. This allows the driver to steer the vehicle to the intended
direction without being disturbed by the steering reaction
force.
* * * * *